1. Technical Field
The present invention relates to a projector.
2. Related Art
Projectors using a high-pressure mercury lamp, a metal halide lamp, or any other suitable discharge lamp have been in practical use. For example, JP-A-2003-102030 discloses a projector having a mechanism for changing the intensity of the light from a light source in accordance with the color selected by a color separation system or any other suitable mechanism and in synchronization with a video signal. JP-A-2009-237302, however, describes that simply changing the intensity of the light from a light source disadvantageously accelerates wear of the electrodes of a discharge lamp.
Further, projectors using a high-pressure mercury lamp, a metal halide lamp, or any other suitable discharge lamp to output stereoscopic video images have recently been brought into practical use.
To output stereoscopic video images, for example, video images for the right and left eyes are switched therebetween and alternately outputted (for example, a method called “XPAND beyond cinema (trademark of X6D Limited)” and other methods based on active shutter eyeglasses). In this method, active shutter eyeglasses or any other device synchronized with a video signal allows a wearer to view right-eye video images with the right eye and left-eye video images with the left eye, whereby the wearer can view the video images stereoscopically with the aid of parallax between the right and left eyes.
When stereoscopic video images are projected by using a method for alternately outputting right-eye video images and left-eye video images, the amount of light incident on the right and left eyes becomes halved or even smaller than a case where planar video images (two-dimensional video images) are projected in related art. Further, if the right-eye video images enters the left eye and the left-eye video images enters the right eye, or crosstalk occurs, the viewer will not view the video images with a sense of three-dimensionality any more. In this case, it is necessary to provide a period during which both the active shutters are closed. As a result, when stereoscopic video images are projected by using a method for alternately outputting right-eye video images and left-eye video images, the video images disadvantageously appear darker than a case where planar video images are projected in related art. To make the video images appear brighter, it is conceivable to simply increase drive electric power. In this case, however, power consumption of the projector disadvantageously increases, and the increase in drive electric power accelerates degradation of peripheral parts and causes other problems.